Automotive vehicles are typically equipped with various user actuatable switches, such as switches for operating devices including powered windows, headlights, windshield wipers, moonroofs or sunroofs, interior lighting, radio and infotainment devices, and various other devices. Generally, these types of switches need to be actuated by a user in order to activate or deactivate a device or perform some type of control function. Proximity switches, such as capacitive switches, employ one or more proximity sensors, such as capacitive sensors, to generate a sense activation field and sense changes to the activation field indicative of user actuation of the switch, typically caused by a user's finger in close proximity or contact with the sensor. Capacitive switches are typically configured to detect user actuation of the switch based on comparison of the sense activation field to a threshold.
Capacitive switches may be manufactured using thin film technology in which a conductive ink mixed with a solvent is printed and cured to achieve an electrical circuit layout. Capacitive switches may also be manufactured using a pre-printed sensor in the form of a flex circuit made of a conductive material, such as copper, and adhered onto a substrate. The capacitive sensors may suffer mechanical/electrical degradation which may lead to failure of the sensor including the routing circuit to the sensor. Degradation of the sensor may cause a change in the capacitive sensor signal which may have a major effect on the signal that is processed to determine an activation of the switch. For example, a hairline crack in the conductive circuitry may cause a significant change in the signal, thus leading to failure. Accordingly, it is desirable to provide for a proximity sensor assembly that can detect the failure of the sensor. It is further desirable to provide for a method of detecting failure of a proximity sensor to lessen any inconvenience to the user.